Method and apparatus for controlling specific service in network congestion state in wireless communication system

ABSTRACT

The present invention relates to a method and apparatus for controlling a specific service in a network congestion state in a wireless communication system. Particularly, the method for controlling a service by a base station in a wireless communication system according to the present invention comprises: a step of receiving a paging message from a mobility management entity (MME) when a certain terminal generates a downlink packet; a step of checking the setup state of the core network domain included in the paging message; and a paging processing step of, if the core network domain is set as a packet-based voice call service, processing the paging message as a priority.

CROSS REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application is a continuation of application Ser. No. 14/428,331,which is the National Stage of International Application No.PCT/KR2013/008354, filed Sep. 16, 2013, which claims foreign priority toKorean Patent Application No. 10-2012-0102035, filed Sep. 14, 2012,Korean Patent Application No. 10-2012-0150620, filed Dec. 21, 2012, andKorean Patent Application No. 10-2013-0027235, filed Mar. 14, 2013, thedisclosures of which are herein incorporated by reference in theirentireties.

TECHNICAL FIELD

The present invention relates to a technology for controlling a servicein a wireless communication system and, in particular, to a method andapparatus for processing the paging for a specific delay-sensitiveservice with priority.

Also, the present invention relates to a method and apparatus forimproving sensible service quality of the UE through service-specificcontrol especially in the network congestion situation.

Also, the present invention relates to a method and apparatus for an IPMultimedia Subsystem (IMS) network to notify the user of call failurecaused by Operator Determined Barring.

BACKGROUND

Mobile communication systems were developed to provide the subscriberswith voice communication services on the move. With the rapid advance oftechnologies, the mobile communication systems have evolved to supporthigh speed data communication services beyond the early voice-orientedservices. However, the limited resource and user requirements for higherspeed services in the current mobile communication system spur theevolution to more advanced mobile communication systems.

As one of the next-generation mobile communication systems to meet suchrequirements, standardization for a Long Term Evolution (LTE) isunderway in the 3^(rd) Generation Partnership Project (3GPP). LTE is atechnology designed to provide high speed packet-based communication ofup to 100 Mbps. In order to accomplish this aim, a discussion is beingheld on several schemes such as reducing the number of nodes located ina communication path by simplifying a configuration of the network andapproximating wireless protocols maximally to wireless channels.

FIG. 1 is a diagram illustrating normal LTE mobile communication systemarchitecture.

As shown in FIG. 1, the radio access network of the LTE mobilecommunication system includes a next generation base station(hereinafter, referred to interchangeably as Evolved Node B (eNB),E-UTRAN, and Node B) 110, a Mobility Management Entity (MME) 120, and aServing Gateway (SGW) 130. The User Equipment (UE) 100 connects to anexternal network via the eNB, the SGW, and a PDN-Gateway (PGW).

The eNB 110 is a Radio Access Network (RAN) node and corresponds to theBSC of the UTRAN system and the BSC of the GERAN system. The eNB 110 isconnected with the UE 100 through a radio channel and performsoperations similar to those of the legacy RNC/BSC. The eNB may use aplurality of cells simultaneously.

In LTE, all of the user traffics including real time service such asVoice over Internet Protocol (VoIP) are provided through a sharedchannel, and thus there is a need of an entity responsible forcollecting status information of the UEs and scheduling based thereonsuch as eNB.

The MME 120 is responsible for various control functions, and aplurality of eNBs may connect to one MME.

The SGW 130 is an entity for providing data bearer which is establishedor released under the control of the MME 120.

The Application Function (AF) 140 is an entity for exchangingapplication information with the user at the application level.

The Policy Charging and Rules Function (PCRF) is an entity forcontrolling policy related to Quality of Service (QoS) of the user andtransfers Policy and Charging Control (PCC) rule corresponding to thepolicy to the PGW 160. The PCRF 150 is an entity of controlling the QoSand billing for traffic. Meanwhile, the term “UP” denotes the pathsconnecting between the UE 100 and the RAN node 110, between the RAN nodeand the SGW 130, and the SGW 130 and the PGW 160 for data transmission.Among them, the path between the UE 100 and the RAN node 110 is a radiochannel which is most resource-restrictive.

In the radio communication system such as LTE, QoS is applied perEvolved Packet System (EPS) bearer. An EPS bearer is used to transmitthe IP flows requiring the same QoS. The EPS bearer may be designatedparameters related to QoS such as QoS Class Identifier (QCI) andAllocation and Retention Priority (ARP). The QCI is a parameter definedas an integer indicating QoS priority, and the ARP is a parameter foruse in determining whether to accept or reject new EPS bearerestablishment.

The EPS bearer corresponds to the Packet Data Protocol (PDP) context ofthe General Packet Radio Service (GPRS). An EPS bearer belongs to a PDNconnection which has the Access Point Name) as an attribute. In the casethat a PDN connection for IP multimedia Subsystem (IMS) service such asVoice over LTE (VoLTE), the corresponding PDN connection is establishedusing the well-known IMS APN.

In order to support voice telephony in the LTE network, it is possibleto use the Packet Switched (PS) mode IMS-based VoLTE or the CS Fall Back(CSFB) reusing the Circuit Switched (CS) mode of the 2^(nd)Generation/3^(rd) Generation (2G/3G) system. VoLTE is the term which canbe used in the same concept as Voice over IMS (VoIMS). The terms “VoLTE”and “IMS voice” are used interchangeably hereinafter.

In the case that the UE is in the idle mode, if downlink data or amobile terminating call addressed to the UE occurs, a paging message istransmitted to notify the UE of the presence of data (or call setup) toreceive. Since the paging resource available in one cell is limited,paging messages for plural UEs are crowded, it may occur to transmit thepaging messages for part of the UEs due to the restricted pagingresource. The voice telephony is a service very sensitive to delay andthus, if the paging signal transmission delay or drop occurs due to thepaging channel congestion, the sensible service quality degradessignificantly.

Meanwhile, various applications are emerged with the widespread use ofsmart phones and, in the LTE system supporting only packet networks, thesmartphone applications are all classified into packet data applicationsalong with the VoLTE and RCT provided by the operator. There istherefore a need of a method for barring the applications discriminatelyin the network overload state.

However, since the barring service is activated according to the user'sregistration as described above, there is a need of defining the UEcontext to be maintained in HSS, TAS, or SCSCF in order for the operatorto bar a certain service arbitrarily. Also, there is no method fornotifying the UE of the UE-initiated session failure caused by theOperator Determined Barring.

SUMMARY

The present invention has been conceived to solve the above problems andaims to provide a method and apparatus for perform the paging for thedelay sensitive service such as voice telephony with priority especiallywhen a plurality of pagings are to be transmitted on the restrictedresource.

Also, the present invention aims to provide a method and apparatus forbarring execution of the applications installed in the UE discriminatelyespecially in the network overload situation.

Also, the present invention aims to notify, when the operator uses theOperator Determined Barring, the UE of this and define a subsequentprocedure of the UE.

In accordance with an aspect of the present invention, a service controlmethod of a serving gateway in a wireless communication system includesreceiving a Packet Data Network (PDN) gateway a packet addressed to aterminal, determining whether the packet is associated with apredetermined service, and transmitting, when the packet is associatedwith the service, to a Mobility Management Entity (MME) a downlink datanotification message configured to process a paging to the terminal withpriority.

In accordance with another aspect of the present invention, a servicecontrol message of a Mobility Management Entity (MME) in a wirelesscommunication system includes receiving a downlink data notificationmessage from a serving gateway, determining whether a paging to acertain terminal is configured to be processed with priority based onthe downlink data notification message, and transmitting, when thepaging is configured to be processed with priority, the pagingconfigured to be processed with priority to a base station.

In accordance with another aspect of the present invention, a servicecontrol method of a Mobility Management Entity in a wirelesscommunication system includes receiving, when a packet addressed to acertain terminal occurs, a downlink data notification message from aserving gateway, determining whether the packet is associated with apredetermined service, and transmitting, when the packet is associatedwith the service, to a base station a paging message configured toprocess a paging to the terminal with priority.

In accordance with another aspect of the present invention, a servicecontrol method of a base station in a wireless communication systemincludes receiving a paging message transmitted by a Mobility ManagementEntity (MME) when a packet addressed to a terminal occurs, determiningwhether a paging to the terminal is configured to be processed withpriority based on the paging message, and processing, when the paging tothe terminal is configured to be processed with priority, the paging tothe terminal with priority.

In accordance with another aspect of the present invention, a servinggateway for controlling services in a wireless communication systemincludes a transceiver which is responsible for transmitting andreceiving to and from nodes of the wireless communication system and acontrol unit which controls receiving a Packet Data Network (PDN)gateway a packet addressed to a terminal, determining whether the packetis associated with a predetermined service, and transmitting, when thepacket is associated with the service, to a Mobility Management Entity(MME) a downlink data notification message configured to process apaging to the terminal with priority.

In accordance with another aspect of the present invention, a MobilityManagement Entity (MME) for controlling services in a wirelesscommunication system includes a transceiver which is responsible fortransmitting and receiving to and from nodes of the wirelesscommunication system and a control unit which controls receiving adownlink data notification message from a serving gateway, determiningwhether a paging to a certain terminal is configured to be processedwith priority based on the downlink data notification message, andtransmitting, when the paging is configured to be processed withpriority, the paging configured to be processed with priority to a basestation.

In accordance with another aspect of the present invention, a MobilityManagement Entity (MME) for controlling services in a wirelesscommunication system includes a transceiver which is responsible fortransmitting and receiving to and from nodes of the wirelesscommunication system and a control unit which controls receiving, when apacket addressed to a certain terminal occurs, a downlink datanotification message from a serving gateway, determining whether thepacket is associated with a predetermined service, and transmitting,when the packet is associated with the service, to a base station apaging message configured to process a paging to the terminal withpriority.

In accordance with still another aspect of the present invention, a basestation for controlling services in a wireless communication systemincludes a transceiver which is responsible for transmitting andreceiving to and from a node or a terminal and a control unit whichcontrols receiving a paging message transmitted by a Mobility ManagementEntity (MME) when a packet addressed to a terminal occurs, determiningwhether a paging to the terminal is configured to be processed withpriority based on the paging message, and processing, when the paging tothe terminal is configured to be processed with priority, the paging tothe terminal with priority.

The present invention is advantageous in terms of protecting against theuser's sensible service quality degradation caused by voice call setupdelay in such a way of preventing the mobile terminating call pagingfrom being delayed or dropped when the mobile terminating call addressedto the UE occurs in the system supporting VoLTE.

Also, the present invention is advantageous in terms of controlling thecongestion efficiently to prevent the service quality from beingdegraded by barring the applications discriminately in the networkoverload situation.

Also, the present invention is advantageous in that the UE is capable ofbeing aware of the session request failure caused by the OperatorDetermined Barring (ODB) and clearing the session immediately.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating normal LTE mobile communication systemarchitecture.

FIG. 2 is a signal flow diagram illustrating exemplary signal flowsamong the wireless communication system nodes according to the firstembodiment of the present invention.

FIG. 3 is a signal flow diagram illustrating other exemplary signalflows among the wireless communication system nodes according to thefirst embodiment of the present invention.

FIG. 4 is a signal flow diagram illustrating still other exemplarysignal flows among the wireless communication nodes according to thefirst embodiment of the present invention.

FIG. 5 is a flowchart illustrating a method for the MME to determinethat the packet addressed to the UE in the idle state is of VoLTE basedon the DDN message received from the SGW.

FIG. 6 is a signal flow diagram illustrating a method for the SGW tonotify the MME whether the user packet received from a PGW is a VoLTE(or IMS voice service) packet according to an example of the firstembodiment of the present invention.

FIGS. 7 and 8 are flowcharts illustrating an operation of notifying MMEof a traffic congestion occurring in a certain channel and the trafficcongestion being resolved according to the first embodiment of thepresent invention.

FIG. 9a is a flowchart illustrating an operation procedure of the MMEreceived the information notifying of the congestion of the pagingchannel from the eNB.

FIG. 9b is a signal flow diagram illustrating signal flows among theintra-network nodes in the congestion situation using a service marking.

FIG. 10 is a signal flow diagram illustrating a procedure of barring theexecution of the applications installed in the UE using the applicationID according to the second embodiment of the present invention.

FIG. 11 is a flowchart illustrating a procedure of determining ofbarring or not when the application barring information set to ‘allowed’is broadcast by the eNB 101.

FIG. 12 is a flowchart illustrating a procedure of barring or not whenthe application barring information set to ‘disallowed’ is broadcastthrough SIB.

FIG. 13 is a diagram illustrating an exemplary application map broadcastby the operator through an eNB.

FIG. 14 is a signal flow diagram illustrating a procedure of barring theexecutions of the applications installed in the UE discriminately usingapplication IDs according to solution 2.

FIG. 15 is a signal flow diagram illustrating a procedure of barring theexecutions of the applications installed in the UE discriminatelyaccording to solution 3 of the second embodiment of the presentinvention.

FIG. 16 is a diagram illustrating an exemplary packet filter structureaccording to an embodiment of the present invention.

FIG. 17 is a signal flow diagram illustrating the procedure of solution4 according to the second embodiment of the present invention.

FIG. 18 is a schematic diagram illustrating EPS and IMS networks asbasis of an embodiment of the present invention.

FIG. 19 is a signal flow diagram illustrating a ‘Barring of all outgoingcall’ operation defined for an IMS network.

FIG. 20 is a signal flow diagram illustrating a procedure for the UE1810 to register with the IMS network and abiding by the ODB accordingto an embodiment of the present invention.

FIG. 21 is a diagram illustrating an exemplary response message proposedin an embodiment of the present invention.

FIG. 22 is a diagram illustrating an exemplary UE context transmittedfrom the HSS to the TAS according to an embodiment of the presentinvention.

FIG. 23 is a diagram illustrating an exemplary XML schema used forimplementing ODB according to an embodiment of the present invention.

FIGS. 24 and 25 are signal flow diagrams illustrating a procedure forthe eNB to notify the MME of the occurrence or resolution of congestionon a specific channel according to an embodiment of the presentinvention.

FIG. 26 is a signal flow diagram illustrating the operation according toanother embodiment of the present invention.

FIG. 27 is a signal flow diagram illustrating the operation according toanother embodiment of the present invention.

Exemplary embodiments of the present invention are described withreference to the accompanying drawings in detail. Detailed descriptionof well-known functions and structures incorporated herein may beomitted to avoid obscuring the subject matter of the present invention.

Although the description is directed to the 3GPP LTE in the embodimentsof the present invention, it will be understood by those skilled in theart that the present invention can be applied even to othercommunication systems having the similar technical background andchannel format, with a slight modification, without departing from thespirit and scope of the present invention.

In the following, descriptions are made of the first to thirdembodiments of the present invention.

The first embodiment is directed to a method of performing the pagingfor a delay sensitive service such as the voice telephony service in asituation where a plurality of pagings are to be transmitted on therestricted resource.

The second embodiment is directed to a method for barring executions ofthe applications installed in the UE discriminately in the networkoverload situation

The third embodiment is directed to a procedure of notifying the UE ofactivation of Operator Determined Barring.

FIRST EMBODIMENT

A description is made of the method of paging for delay sensitiveservice such as voice telephony with priority according to the firstembodiment.

In the first embodiment, an example of the delay sensitive service is apacket-based voice call. The packet-based voice call is a conceptcontrasting the legacy circuit-based voice call and may include VoLTEcall and VoIMS call. In the following description, it is assumed thatthe packet-based voice call is the VoLTE call for convenience purpose.

FIG. 2 is a signal flow diagram illustrating exemplary signal flowsamong the wireless communication system nodes according to the firstembodiment of the present invention.

In the case that a downlink packet addressed to the UE 210 in the idlestate arrives at the SGW 240, the SGW 240 sends the MME 230 a DownlinkData Notification (DDN) message at step S205. The DDN message includesan EPS bearer Identifier (ID) for identifying the EPS bearer carryingthe packet.

If the QCI of the EPS bearer is 1 or 5 based on the EPS bearer contextindicated by the EPS bearer ID, the MME 230 determines that the VoLTEcall is made at step S210. In the case of VoLTE, the EPS bearer isidentified with QCI 1 (media bearer) or QCI 5 (IMS signaling bearer).The MME 230 may check the APN of the PDN connection to which thecorresponding EPS bearer belongs and, if it matches the IMS APN, becomeaware of the occurrence of VoLTE call.

If the VoLTE call occurrence is detected as above, the MME 230 sets thecore network (CN) domain, which is included in the paging messagetransferred to the eNB 220, to Circuit Switched (CS) even though theVoLTE call is the service supported through the PS core network. Inorder to increase the paging success probability, it may be possible totransmit the paging message to the eNBs within the area larger than thatfor the normal PS domain paging (i.e. plural cells or plural TAs). TheeNBs within the large area means at least one eNB, i.e. plural eNBs.This is because if the paging message is transmitted to one eNB thepaging is likely to fail due to the UE mobility but if the pagingmessage is transmitted to multiple eNBs it is possible to prepare forthe UE mobility.

If there is no reply from the UE in response to the paging message, thepaging is repeated more frequently than the normal data packet, and thetimer for determining the failure of receiving the paging response (i.e.Service Request) is set to a value different from that of the timerdetermining failure of receiving the paging response for a normal datapacket.

At the same time, the MME 230 sets the ‘CS paging for VoIMS’ flag of theUE context to true to memorize the transmission of the CS paging forVoLTE call as PS data.

Then the eNB 220 is configured such that the CN domain transmit the CSpaging with priority as compared to the PS paging by taking notice ofthe characteristic of the delay-sensitive CS call at step S220.

The eNB 220 sends the UE 210 the paging with priority as compared to thePS domain paging according to the configuration at step S225.

Upon receipt of the paging from the eNB 220, the eNB 210 sends the MME230 an Extended Service Request message including a CSFB responseindicator IE set to mobile terminating CS fallback or 1×CS fallback atstep S230.

Upon receipt of the Extended service Request message from the UE 210,the MME 230 becomes aware of the “CS paging for VoIMS” which is set toTrue for the corresponding UE at the previous step although the UEincludes the CSFB response indicator in the Extended Service Requestmessage, at step S235. Accordingly, the MME 230 is aware of theoccurrence of the VoLTE call other than CS call and performs a normalservice request process subsequently instead of the CSFB process.

Accordingly, the MME 230 sends the eNB 220 an Initial Context SetupRequest message at step S240, and the eNB 220 sends the UE an RRCConnection Reconfiguration message for Data Radio Bearer (DRB)establishment at step S245.

If the RRC Connection Reconfiguration message for DRB configuration isreceived from the eNB 220, the UE 210 is aware that the Extended ServiceRequest message has been transmitted successfully at step S250.

In detail, if the UE performing PS-based communication has transmittedthe extended service request in response to the CS paging, it isdetermined that the extended service request is successful only when thesystem change to the CS network is performed.

In the present invention, if the UE which has received the CS pagingtransmits the extended service request, it is determined that theextended service request is performed successfully when a bearerconfiguration message generated according to the legacy PS-based servicerequest operation is received other than when the system is changed.

Summarizing the embodiment of FIG. 2, the MME 230 instructs the eNB 220to transmit the CS paging, in spite of occurrence of the PS call otherthan CS call to the UE 210, and records this situation in the UEcontext. Since the UE 210 has received the CS paging from the eNB 220,it transmits the Extended Service Request message to the MME 230, andthe MME 230 checks the recorded UE context to recognize that theCS-extended service request of the UE is the PS service request and thusperforms a procedure based on the PS service request.

FIG. 3 is a signal flow diagram illustrating other exemplary signalflows among the wireless communication system nodes according to thefirst embodiment of the present invention.

If the downlink packet addressed to the UE 310 in the idle state arrivesat the SGW 340, the SGW 340 sends the MME 330 a Downlink DataNotification (DDN) message. The DDN message includes an EPS bearerIdentifier (ID) for identifying the EPS bearer carrying the packet.

If the QCI of the EPS bearer is 1 or 5 based on the EPS bearer contextindicated by the EPS bearer ID, the MME 330 determines that the VoLTEcall is made at step S320. In the case of VoLTE, the EPS bearer isidentified with QCI 1 (media bearer) or QCI 5 (IMS signaling bearer).The MME 330 may check the APN of the PDN connection to which thecorresponding EPS bearer belongs and, if it matches the IMS APN,recognize the occurrence of VoLTE call.

If the VoLTE call occurrence is detected as above, the MME 330 sets thecore network (CN) domain, which is included in the paging messagetransferred to the eNB 320, to Circuit Switched (CS) even though theVoLTE call is the service supported through the PS core network. Inorder to increase the paging success probability, it may be possible totransmit the paging message to the eNBs within the area larger than thatfor the normal PS domain paging (i.e. plural cells or plural TAs). TheeNBs within the large area means at least one eNB, i.e. plural eNBs.This is because if the paging message is transmitted to one eNB thepaging is likely to fail due to the UE mobility but if the pagingmessage is transmitted to multiple eNBs it is possible to prepare forthe UE mobility.

If there is no reply from the UE in response to the paging message, thepaging is repeated more frequently than the normal data packet, and thetimer for determining the failure of receiving the paging response (i.e.Service Request) is set to a value different from that of the timerdetermining failure of receiving the paging response for a normal datapacket.

At the same time, the MME 330 sets the ‘CS paging for VoIMS’ flag of theUE context to true to memorize the transmission of the CS paging forVoLTE call as PS data.

Then the eNB 320 is configured such that the CN domain transmit the CSpaging with priority as compared to the PS paging by taking notice ofthe characteristic of the delay-sensitive CS call at step S340.

The eNB 320 sends the UE 310 the paging with priority as compared to thePS domain paging according to the configuration at step S350.

Upon receipt of the paging from the eNB 230, although the cn_Domain ofthe paging message is set to CS, if an ‘IMS voice over PS session in S1mode supported’ is received through the ‘EPS network feature support IE’of the most recent Attach Accept message or TAU accept message and ifthe IMS registration is successful, the UE 310 sends the MME 330 aservice request message for PS service instead of the Extended ServiceRequest message for CSFB at step S370.

According to the embodiment of FIG. 3, if a specific condition isfulfilled, the UE 310 sends the MME 330 a service request message for PSservice instead of the Extended Service Request message for CS service,although the CS paging is received.

FIG. 4 is a signal flow diagram illustrating still other exemplarysignal flows among the wireless communication nodes according to thefirst embodiment of the present invention.

If the downlink packet addressed to the UE 410 in the idle state arrivesat the SGW 440, the SGW 440 sends the MME 430 a Downlink DataNotification (DDN) message. The DDN message includes an EPS bearerIdentifier (ID) for identifying the EPS bearer carrying the packet.

If the QCI of the EPS bearer is 1 or 5 based on the EPS bearer contextindicated by the EPS bearer ID, the MME 430 determines that the VoLTEcall is made at step S420. In the case of VoLTE, the EPS bearer isidentified with QCI 1 (media bearer) or QCI 5 (IMS signaling bearer).The MME 430 may check the APN of the PDN connection to which thecorresponding EPS bearer belongs and, if it matches the IMS APN,recognize the occurrence of VoLTE call.

In this case, the MME 430 sends the eNB 420 the paging message includingthe information notifying of the paging for VoLTE service although theCN domain is PS. As shown in the drawing, it is an example that the CNdomain of the paging message is set to PS_Voice. In another example, theMME may include a Voice indicator indicating that the correspondingservice is associated with the voice call along with the CN Domain setto PS in the paging message. In order to increase the paging successprobability, it may be possible to transmit the paging message to theeNBs within the area larger than that for the normal PS domain paging(i.e. plural cells or plural TAs). The eNBs within the large area meansat least one eNB, i.e. plural eNBs. This is because if the pagingmessage is transmitted to one eNB the paging is likely to fail due tothe UE mobility but if the paging message is transmitted to multipleeNBs it is possible to prepare for the UE mobility.

If there is no reply from the UE in response to the paging message, thepaging is repeated more frequently than the normal data packet, and thetimer for determining the failure of receiving the paging response (i.e.Service Request) is set to a value different from that of the timerdetermining failure of receiving the paging response for a normal datapacket.

Although the CN domain is PS, if it is recognized that the paging isrelated to the VoLTE service, i.e. if the paging is related to thepacket-based voice call service, the eNB 420 is configured to transmitthe corresponding paging with priority. As shown in the drawing, if theCN domain of the paging message is set to PS_Voice, this paging istransmitted with priority as compared to the paging message of which CNdomain is set to PS. Upon receipt of this, the UE performs the normalService Request process.

According to the embodiment of FIG. 4, if downlink data, particularlyVoLTE, addressed to the UE 410 occurs, the MME 430 sends the eNB 420 thepaging information including an indicator informing of the occurrence ofthe packet-based voice call service. Then the eNB 420 processes thepaging for the packet-based voice call service with priority as comparedto the CS service.

FIG. 5 is a flowchart illustrating a method for the MME to determinethat the packet addressed to the UE in the idle state is of VoLTE basedon the DDN message received from the SGW.

If a downlink packet addressed to the UE in the idle state arrives atSGW, the MME receives the Downlink Data Notification (DDN) message fromthe SGW at step S510. The DDN message includes an EPS bearer Identifier(ID) for identifying the EPS bearer carrying the packet.

If the QCI of the EPS bearer is 1 or 5 based on the EPS bearer contextindicated by the EPS bearer ID, the MME determines that the VoLTE callis made at step S520. In the case of VoLTE, the EPS bearer is identifiedwith QCI 1 (media bearer) or QCI 5 (IMS signaling bearer). The MME 530may check the APN of the PDN connection to which the corresponding EPSbearer belongs and, if it matches the IMS APN, recognize the occurrenceof VoLTE call. The MME operation in FIG. 5 may be used along with theembodiments of FIGS. 2 to 4.

As a result, if either the CQI of the EPS bearer is 1 or 5 or the APN ofthe PDN connection is identical with the IMS APN at step S520, the MMEdetermines that the corresponding downlink packet is of VoLTE at stepS530. Otherwise, the MME determines that the corresponding downlinkpacket is not of VoLTE at step S540. In this case, the MME may transmitthe paging message to the eNBs within the area larger than that for thenormal PS domain paging (i.e. plural cells or plural TAs) in order toincrease the paging success probability. The eNBs within the large areameans at least one eNB, i.e. plural eNBs. This is because if the pagingmessage is transmitted to one eNB the paging is likely to fail due tothe UE mobility but if the paging message is transmitted to multipleeNBs it is possible to prepare for the UE mobility.

If there is no reply from the UE in response to the paging message, thepaging is repeated more frequently than the normal data packet, and thetimer for determining the failure of receiving the paging response (i.e.Service Request) is set to a value different from that of the timerdetermining failure of receiving the paging response for a normal datapacket.

FIG. 6 is a signal flow diagram illustrating a method for the SGW tonotify the MME whether the user packet received from a PGW is a VoLTE(or IMS voice service) packet according to an example of the firstembodiment of the present invention.

By referencing that the context of the bearer to which the packetreceived from the PGW 610 belongings, if the QCI of the correspondingEPS bearer is 1 or 5, the SGW 620 determines the occurrence of the VoLTEcall. This is because the EPS bearer is identified with QCI 1 (mediabearer) or QCI 5 (IMS signaling bearer) in the case of VoLTE.

The SGW 520 checks the APN of the PDN connection to which thecorresponding EPS bearer belongs and, if it matches the IMS APN,recognizes the occurrence of VoLTE call. In this case, the SGW 620 mayinsert the IE notifying of VoIMS or the priority level set to high inthe DDN message transmitted to the MME 610. At this time, the servicetype or priority level may be indicated by means of the ARP. Forexample, ARP 0 may indicate the service with the highest paging priorityand ARP 1 the service with the next highest priority.

If the DDN message is received from the SGW 620, the MME checks the DDNindicates the VoLTE or high priority and then omits the operation foridentifying the VoLTE call when performing the operations correspondingto FIGS. 2 to 4. In order to increase the paging success probability, itmay be possible to transmit the paging message to the eNBs within thearea larger than that for the normal PS domain paging (i.e. plural cellsor plural TAs). The eNBs within the large area means at least one eNB,i.e. plural eNBs. This is because if the paging message is transmittedto one eNB the paging is likely to fail due to the UE mobility but ifthe paging message is transmitted to multiple eNBs it is possible toprepare for the UE mobility.

If there is no reply from the UE in response to the paging message, thepaging is repeated more frequently than the normal data packet, and thetimer for determining the failure of receiving the paging response (i.e.Service Request) is set to a value different from that of the timerdetermining failure of receiving the paging response for a normal datapacket.

FIGS. 7 and 8 are signal flow diagrams illustrating methods for an eNBto notify an MME of congestion occurrence and resolution on a specificchannel according to the first embodiment of the present invention.

In this embodiment, the description is made of the exemplary case wherethe paging channel is congested. If the paging channel is congested, theeNB 710 sends the MME 720 an Overload Start message at step S710. Thismessage may include a PLMN ID and cell ID of the cell in which thecongestion has occurred, the congested channel (paging channel in thisembodiment), congestion level or load level required to resolve thecongestion, and congestion continuation time.

If the Overload Start message is received from the eNB 710, the MMEassumes that the corresponding channel of the corresponding cell iscongested afterward and, if the Overload Start message includes thecongestion continuation time, starts a timer to check the expiry of thecongestion time.

As shown in FIG. 8, the MME 720 may receive an Overload Stop messagenotifying that the congestion is resolved in the corresponding cell fromthe eNB 710 at step S810. Then the MME 720 assumes that the congestionhas been resolved on the corresponding channel of the correspondingcell. If the Overload Start message includes the congestion continuationtime the MME assumes that the congestion continues until the timeexpires. The MME may start a timer according to its internal time, evenwhen the Overload Start message has no congestion continuation time, tocount the running duration of the timer as the continuation of thecongestion.

If the congestion occurs or is resolved on a specific channel (pagingchannel in this embodiment) of a specific cell of the eNB, the eNBnotifies the MME of this through S1AP signaling as shown in FIGS. 7 and8 or using a O&M method in another embodiment. This may include aprocedure for the eNB to notify the O&M server of its congestion stateand a procedure for the O&M server to notify other nodes (MME, PGW,etc.) of the eNB congestion state. The messages exchanged between thenodes include the information similar to that mentioned in thedescriptions of FIGS. 7 and 8. Upon receipt this message, the MME andPGW assume that the congestion has occurred or has been resolved on thespecific channel of the specific cell of the corresponding eNB.

FIG. 9a is a flowchart illustrating an operation procedure of the MMEreceived the information notifying of the congestion of the pagingchannel from the eNB.

The MME 720 receives a DDN message for the UE in the idle mode from theSGW at step S910. Then the MME 720 selects candidate cells fortransmitting the paging message based on the stored context at step 920.The MME 720 determines whether the overload start message notifying ofthe congestion on the paging channel is received from each candidatecell at step S930.

If the overload start message is received from the corresponding cell,the MME 720 checks that the service type of the packet corresponding tothe DDN is VoLTE or a service with a high priority through theabove-described method (method of FIG. 5 in which the MME checks itautonomously or the method of FIG. 6 in which the SGW informs of itthrough DDN) at step S940. If the service type of the packet is VoLTE ora service with a high priority, the MME 720 transmits the paging messageto the corresponding cell with priority at step S950. At this time, theMME 720 sets the CN domain of the paging message to PS.

If the EPS bearer recognized by the DDN is not for VoLTE service or theservice with a high priority, the MME 720 decreases the transmissionpriority of the paging message until the overload stop message notify ofthe end of the congestion on the paging channel of the correspondingcell is received from the eNB using the corresponding cell.

In the above embodiment, it is noted that the congestion report processis not mandatory. That is, although a cell of the specific eNB does notsend any congestion report, the MME may transmit the paging for theVoLTE service with priority as compared to the paging for the normal PSdata service.

Through the embodiment of FIG. 9a , the MME 720 may determine whether totransmit the paging message based on the paging channel stateinformation of the cell notified by the eNB. In this way, it is possibleto transmit the paging for the VoLTE service with priority through thecongested paging channel. It is also possible to determine whether totransmit the paging depending on the congestion status of the eNBthrough above described O&M-based method.

FIG. 9b is a signal flow diagram illustrating signal flows among theintra-network nodes in the congestion situation using a service marking.

As described with reference to FIGS. 7 and 8, if a specific channel of aspecific cell of the eNB is congested, the eNB may notify the MME andPGW of the congestion state through the signaling method or the O&Mmethod, and the PGW/TDF/MME operation to be described with reference toFIG. 9b may be performed in consideration thereof. However, it is notedthat the embodiment of FIG. 9b may not include the above congestionreport procedure.

The UE performs a network attach procedure at step S970 and, if thenetwork attach procedure is completed, enters the idle mode at stepS972. If congestion occurs in a specific cell or on a specific channelof the eNB, the eNB notifies of the MME of the congestion.

If a downlink packet addressed to the UE occurs at step S976, theTraffic Detection Function (TDF) or the PGW analyzes the content of thedownlink packet and inserts the service information into the ServiceClass Identity (SCI) field of the header (GTP-U) of the packettransferred to the next node at step S978. In an embodiment of thepresent invention, the SCI value may be used as an identifier foridentifying PS-based voice call service or other service (messaging,video telephony, Rich Communication Suite (RCS)).

If the header of the GTP-U packet received from the TDF or PGW includesa marked SCI field, the SGW extracts it at step S984. Then the SGW sendsthe MME the DDN message including the SCI field at step S986.

Upon receipt of the DDN, the MME selects a candidate cell fortransmitting the paging and, if the paging channel of the cell iscongested, checks the SCI field which the SGW has inserted in the DDN atstep S988. If it is determined that the paging is for the PS voice callservice or a service with a high priority, the MME processes the pagingwith priority at step S990 and, otherwise, performs a determinationprocess for delaying the paging.

The above embodiments may be extended to an embodiment may be extendedto an embodiment of processing, when the congestion occurs between thecontrol plane (eNB) and the core network or at the control signalingexchange part among the core network entities, the paging for theservice with a high priority such as PS voice call with priority andthen the padding for the service with a low priority.

If the congestion occurs on the control plane (e.g. the paging signalprocessing overload occurs at the eNB or the MME), another effectivemethod for reducing the signaling on the control plane is to throttlethe DDN messages transmitted by the SGW when the downlink messageaddressed to the UE in the idle state occurs. If a downlink messageaddressed to the UE in the idle state occurs, the SGW sends the MME theDDN message, and the MME transmits the paging request to the eNB(s)based on the DDN message. The eNB(s) transmits the paging message. Ifthe paging message is received, the UE performs a service requestprocess for receiving the downlink message. The DDN transmitted by theSGW causes several control messages such as paging and service request,this is likely to contribute to the congestion on the control plane.

In order to solve the above problems, when the congestion occurs on thecontrol plane, the MME may request the SGW to throttle the number ortransmission frequency of the DDN messages. In this requesting process,the MME may be aware of the services of which DDN messages are to bethrottled or allowed and may provide with the information for use indetermining the time of applying the throttling. Upon receipt of therequest, if the downlink message to be delivered to the UE belongs tothe target service, the SGW determines whether to transmit the DDNmessage according to the throttling factor and throttling delay.

FIG. 26 is a signal flow diagram illustrating the operation according toanother embodiment of the present invention.

The MME determines whether congestion occurs on the control plane atstep S2610. The determination may be made in such a way of comparing itsprocessing amount and the number of tasks (or messages) to be processedor, when the connected eNBs has informed of the congestion at stepS2605, considering the congestion information (e.g. the informationnotifying that the congested channel is the paging channel).

Afterward, if the DDN message is received form the SGW at step S2615,the MME sends the SGW a DDN Acknowledge (Ack) message including anInformation Element (IE) indicating that the number of DDN messages hasto be decreased due to the congestion (e.g. DL traffic throttling IE) atstep S2620.

At this time, the above IE may include at least one of throttlingtarget, throttling exception target, throttling delay, and throttlingfactor as the information for use in controlling the DDN message at theSGW.

In the case that the throttling target is includes, if the downlinkmessage is included in the throttling target, the SGW applies the DDNtransmission throttling at step S2625. In the case that the throttlingexception target is included, if the downlink message is included in thethrottling exception target, the SGW does not apply the DDN transmissionthrottling. At this time, the information for identifying the target maybe any of Allocation and Retention Priority (ARP), QoS Class Identifier(QCI), UE identifier, and Service Class Identifier (SCI). In the casethat the throttling delay is included, the SGW applies the throttlingduring the throttling delay. The throttling factor is a value indicatingthe ratio of the message to be throttled to the entire DDN messagessupposed to be transmitted.

If no throttling/exception target is included in the throttling requestof the MME, the SGW may determine the throttling target based on apredetermined ARP or QCI.

For example, the DDN Ack message sent by the MME includes the exceptiontarget identified by QCI set to 5, throttling delay set to 10, andthrottling facto set to 40, the SGW sends the MME 60% of the DDNmessages necessary for the packets belonging to the bearer of which QCIis not 5 for 10 seconds. If the DDN Ack message sent by the MME includesthe exception target identified by SCI of the messenger service,throttling delay set to 10, and throttling factor set to 40, the SGWcompares the target CSI with the SCI field of the GTP-U header of thepacket received from the PGW to send the MME 60% of the DDN messagesnecessary for the packets having the matched CSI for 10 seconds. If theMME notifies of only the throttling delay set to 10 and throttlingfactor set to 40% and if the SGW is configured to do not apply thethrottling to the packets belonging to the bearer of which QCI is 5, theSGW sends the MME 60% of the DDN messages necessary for the packetsbelonging to the bearer of which QCI is not 5 for 10 seconds.

Meanwhile, when the congestion occurs on the control plane, the DDNmessage throttling may be requested by means of a separate message otherthan the DDN Ack message.

FIG. 27 is a signal flow diagram illustrating the operation according toanother embodiment of the present invention.

The MME determines whether congestion occurs on the control plane atstep S2610. The determination may be made in such a way of comparing itsprocessing amount and the number of tasks (or messages) to be processedor, when the connected eNBs has informed of the congestion at stepS2705, considering the congestion information (e.g. the informationnotifying that the congested channel is the paging channel).

Afterward, the MME sends the SGW a message requesting for throttling thenumber of DDN messages due to the congestion (e.g. overload start orerror indication message) at step S2715. At this time, this message mayinclude at least one of throttling target, throttling exception target,throttling delay, and throttling factor, as the information for use incontrolling the DDN messages at the SGW.

In the case that the throttling target is includes, if the downlinkmessage is the target, the SGW applies the DDN transmission throttlingat step S2720.

In the case that the throttling exception target is included, if thedownlink message is the target, the SGW does not apply the DDNtransmission throttling. At this time, the information for identifyingthe target may be any of Allocation and Retention Priority (ARP), QoSClass Identifier (QCI), UE identifier, and Service Class Identifier(SCI). In the case that the throttling delay is included, the SGWapplies the throttling during the throttling delay. The throttlingfactor is a value indicating the ratio of the message to be throttled tothe entire DDN messages supposed to be transmitted. If nothrottling/exception target is included in the throttling request of theMME, the SGW may determine the throttling target based on apredetermined ARP or QCI. The operation of the SGW which receives thismessage is identical with that in the DDN Ack-based embodiment. If thecongestion on the control plane is resolved, the MME sends the SGW amessage for notifying that the DDN message throttling is not necessaryany more, e.g. overload stop message, explicitly.

SECOND EMBODIMENT

A description is made of the second embodiment which is directed to amethod of controlling execution of the applications installed in the UEdiscriminately in a network overload situation hereinafter.

1) Solution 1: Method of Using Application ID

FIG. 10 is a signal flow diagram illustrating a procedure of barring theexecution of the applications installed in the UE using the applicationID according to the second embodiment of the present invention.

The UE 1000 performs a network attach procedure at step S1000. Then theoperator configures the application name and application ID to the UEthrough OMA-DM at step S1005. The UE frame work & modem 1002 of the UE1000 stores the application name and application ID.

Afterward, the operator broadcasts the IDs of the applications to bebarred access to the network and parameters for barring through the SIBof the eNB at step S1030. The parameters may include the barring timeand the barring factor.

Meanwhile, when the application 1001 of the UE 1000 opens a socket fordata transmission/reception, the application 1001 sends the UE frameworkand modem 1002 the parameters such as the name of the correspondingapplication and application ID received from the operator at step 1015.

The OS or the service frame work, i.e. the UE framework and modem 1002,of the UE which generates the socket and allocates port number storesallocated port number and UE address, the application name as parametertransmitted by the application 1001, and application ID mapped to theapplication name allocated by the operator. That is, the source addressand source port used by the application 1001 and the ID set by theoperator for the application are mapped to be stored.

At step S1025, when the application 1001 is about to transmit data andthus a request for transitioning to the connected mode is transmitted,whether to bar the transmission is determined.

The determination on whether to bar the transmission is performed atstep S1035 based on the mapping information stored by the UE frameworkand modem 1002. The UE framework and modem 1002 checks the applicationID mapped to the source address and source port in the stored mappinginformation. The UE framework and modem 1002 determines whether thecorresponding application ID is barred in the application barringinformation included in the SIB broadcast by the eNB 1010.

If the corresponding application ID is barred, the UE framework andmodem 1002 notifies the application 1001 of rejection at step S1040.Otherwise if the application ID is not barred, the UE framework and mode1002 sends the network a service request to transition to the connectedmode at step S1050.

The procedure of determining of barring or not at the UE framework andmodem 1002 at step S1035 of FIG. 10 is described in detail withreference to FIGS. 11 and 12. FIG. 11 is a flowchart illustrating aprocedure of determining of barring or not when the application barringinformation set to ‘allowed’ is broadcast by the eNB 101.

The UE framework and modem 1002 checks the application ID and indexmapped to the source address and port number of the IP packet receivedfrom the application 1001 at step S1110. Next, the UE framework andmodem 1002 determines whether the application ID or index is broadcastby the eNB at step S1115.

As shown in FIG. 10, if the application barring information is definedto be broadcast as set to ‘allowed’ but the not broadcast by the eNB,the UE framework and modem 1002 sends the application 1001 a messagerejecting the data transmission at step S1120.

In the flowchart of FIG. 10, otherwise, if the application barringinformation is defined to be broadcast as set to ‘allowed’ and if thebarring information is broadcast by the eNB, the UE framework and modem1002 determines whether the load factor of the barring factor is a valuebetween 0 and 1 at step S1125. In the case that the load factor is not avalue between 0 and 1, if the load factor is 0, the UE framework andmodem 1002 sends the application 1001 a message rejecting datatransmission at step S1130. Otherwise if the load factor is 1, the UEframework and modem 1002 sends the network a service request fortransition to the connected mode at step S1135.

In the case that the load factor is a value between 0 and 1, the UEframework and modem 1002 generates a random number and compares therandom number and the load factor in size at step S1140. If the randomnumber is greater than the load factor, the UE framework and modem 1002sends the network a service request for transitioning to the connectedmode at step S1145. Otherwise if the random number is less than the loadfactor, the UE framework and modem 1002 sends the application 1001 amessage rejecting the data transmission at step S1130.

Summarizing the embodiment of FIG. 11, the application ID of theapplication to execute is not carried in the SIB of the eNB, the UEregards the application as a barring target and applies the barringfactor. When applying the load factor as barring factor, the UE sendsthe eNB a value between 0 and 1 as the load factor, generates a randomnumber between 0 and 1 and, if the random number is greater (or less)than the number broadcast by the eNB, regards that the application haspassed the barring to transmit a connection request. If it fails to passthe barring, i.e. if barred, the UE framework and modem notifies theapplication 1001 that the data transmission is rejected.

FIG. 12 is a flowchart illustrating a procedure of barring or not whenthe application barring information set to ‘disallowed’ is broadcastthrough SIB. That is, if the barring information is not broadcast, it isdetermined that the target is not barred and, if broadcast, determineswhether to apply the barring.

The UE framework and modem 1002 checks the application ID and indexmapped to the source address and port number of the IP packet receivedfrom the application 1001 at step S1210. Next, the UE framework andmodem 1002 determines whether the application ID or index is broadcastby the eNB at step S1215.

If the application ID or index is not broadcast, the UE framework andmode 1002 sends the network a service request for transitioning to theconnected mode at step S1220.

If the application ID or index is broadcast, the UE framework and modem1002 determines whether the load factor of the barring factor is a valuebetween 0 and 1. In the case that the load factor is not a value between0 and 1, if the load factor is 1, the UE framework and modem 1002 sendsthe application 1001 a message rejecting data transmission at stepS2130. Otherwise if the load factor is 0, the UE framework and modem1002 sends the network a service request for transition to the connectedmode at step S1235.

In the case that the load factor is a value between 0 and 1, the UEframework and modem 1002 generates a random number and compares therandom number and the load factor in size at step S1240. If the randomnumber is less than the load factor, the UE framework and modem 1002sends the network a service request for transitioning to the connectedmode at step S1245. Otherwise if the random number is greater than theload factor, the UE framework and modem 1002 sends the application 1001a message rejecting the data transmission at step S1230.

The solution 1 is simple because of using OMA-DM and has threecharacteristics as follows.

1) Since only the home operator can apply the UE configuration usingOMA-DM due to the authentication and OMA-DM server configurationproblem, it is necessary for the UE to store the application name and IDconfiguration lists used by the roaming partners per roaming partner forroaming and, if a list is updated by the corresponding roaming partner,update the corresponding list.

2) The information amount to be broadcast increases in proportion to thenumber of application to which the barring information identical in sizewith the application ID.

Ex) If the application ID is 32-bit long, the broadcast informationamount becomes application ID size (32 bits)×number of applications(application_num)+barring information size (barring-info-size) accordingto the number of the application to which the same barring informationis applied.

3) All the operators have to use the same application names. Althoughdifferent application IDs can be used, but the application names have tobe identical each other.

2) Solution 2: Method of Using Application Index

The second characteristic of solution 1 is can be solved in such a wayof configuring the application index value, instead of the applicationID, to the UE and broadcasting a map (e.g. bitmap) in which the xth bitof the index is marked so as to reduce the information amount.

A description is made of solution 2 with reference to FIGS. 13 and 14.

FIG. 13 is a diagram illustrating an exemplary application map broadcastby the operator through an eNB.

FIG. 14 is a signal flow diagram illustrating a procedure of barring theexecutions of the applications installed in the UE discriminately usingapplication IDs according to solution 2.

The operator configures the application index, application name, andapplication ID to the UE using OMA-DM at step S1410. In the case of theformat of (application index, application name, application ID), it canbe configured in such a way of (1, KakaoTalk, 112345) and (6, skype,1234234).

Then the operator broadcasts the SIB including the application mapformatted as shown in FIG. 13. In the application map depicted in FIG.13, the first and sixth bits are marked such that the UE determines thecorresponding applications as the barring targets.

The barring procedure of using the application index as shown in thesignal flow diagram of FIG. 14 is identical in order with that of FIG.12 with the exception that the information configured through the OMA-DMat step S1410 includes the application index and the barring target isdetermined based on the marking made in the application map other thanthe presence of the application ID. Thus, detailed description on FIG.14 is omitted herein. The second solution is capable of solving thecharacteristic 2 of solution 1 by reducing the broadcast informationamount.

3) Solution 3: Method of Using VPLMN Signaling

Solutions 1 and 2 use OMA-DM such that the home operator has toconfigure even the information of the list to be used in all the roamingpartners. In order to solve this problem, solution 3 proposes a methodfor the roaming partner to provide the list directly through PCOsignaling as shown in FIG. 15.

FIG. 15 is a signal flow diagram illustrating a procedure of barring theexecutions of the applications installed in the UE discriminatelyaccording to solution 3 of the second embodiment of the presentinvention.

Descriptions are made of the respective steps of FIG. 15 hereinafter.

-   -   S1505: The UE sends the MME an attach request message including        a PDN connection request message for establishing a default PDN        connection as an ESM message. Here, the PDN connection request        message includes a Protocol Configuration Option (PCO) set to        ‘application barring enabled.’    -   S1510: Upon receipt of the attach request message, the MME sends        the SGW/PGW a Create Session Request message for establishing        the default PDN connection, the Create Session Request message        including the PCO value as received from the UE.    -   S1515, S1520: If the application barring enabled is configured,        the PGW sends an application control server an application list        request message to acquire the application list including the        application index, application ID, and application name. In the        case of using the application list configured in the PGW, steps        S1515 and 1520 are omitted.    -   S1525: The PGW sends the MME a Create Session Response message        including the PCO set to the application list.    -   S1530: If the PCO set to the application list is received from        the PGW, the MME sends the UE an Attach Accept message including        the application list. In detail, the MME copies the application        list to the PCO in the Activate Default EPS Bearer Context        Request message to be transmitted to the UE and includes this        message in the Attach Accept message.    -   S1535: Upon receipt of the application list from the MME through        PCO, the UE stores the application list for use afterward. The        stored application list is handled in valid in the registered        PLMN representing the currently registered operator network and        its equivalent PLMN. Then the rest part of the attach procedure        progresses.    -   S1540: The application of the UE sends the UE framework and        modem (OS/service Framework) the application name as one of the        parameters to request for communication service open for data        transmission.    -   S1545: Upon receipt of the application execution request, the UE        framework and modem (OS/service framework) allocates a source        port, retrieves the application index and application ID from        the application list received at step S1530 based on the        application name received from the application, maps the        application index and ID to the allocated port number, and        stores the mapping relationship.    -   S1550: The UE transmits the data through the port allocated to        the application.    -   S1555: Meanwhile, the eNB broadcasts the SIB including the        application barring information set to allowed or disallowed and        application map information.    -   S1560: If the IP data is received, the UE framework and modem        (OS/service framework determines whether the application ID or        application index mapped to the source address and port of the        IP data is barred based on the SIB broadcast by the eNB. The        determination is made as described with reference to any of        FIGS. 11 and 12.    -   S1565: If it is determined that the application is a barring        target, the procedure goes to process A to notify the        application that the transmission is not allowed.

Otherwise if it is determined that the application is not a barringtarget, the procedure goes to process B to send the network a servicerequest for transitioning to the connected mode for data transmission.

The method in the UE notifies the network that the application barringis enabled (application-barring-enabled) through PCO and the networksends the UE the application list as shown in FIG. 15 may be applicablefor all the messages capable of being transmitted through PCO.

In FIG. 15, it is assumed that the MME of the roaming network uses thePGW of the roaming network when configuring the application list usingthe PCO.

If the MME of the roaming network cannot use the PGW of the roamingnetwork but the PGW of the home network, the MME checks that thereceived PCO is set to application-barring-enabled and stores thecorresponding value, the application-barring-enabled value being erasedwhen the Create Session Request/Update Bearer Request message istransmitted to the SGW/PGW at step S1510.

Afterward, when transmitting the Attach Accept/TAU Accept message to theUE after the receipt of the Create Session Response/Update BearerResponse message at step S1525, the MME modifies the PCO content bysetting the PCO to ‘application list’ and sends the UE the applicationlist of the roaming network.

Like the solution 2, the solution 3 uses the application index to reducethe information amount to be broadcast while allowing the home operatorto do not configure the information of the roaming partner while

4) Solution 4: Method of Using Packet Filter

The solutions 1, 2, and 3 are on the assumption that the operators usethe same application name. In order to overcome the situation of usingdifferent application names, the solution 4 proposes a method of using apacket filter.

The network transmits an Activate Default EPS Bearer Context Requestalong with the Attach Accept message when establishing the defaultbearer in the attach procedure of the UE and, at this time, designatesan application using the packet filter. That is, the network configuresthe application index or application ID value in the packet filteridentified by a source address, a source port, a receiver address, and areceiver port corresponding to the application traffic such that the UEstores such information.

An exemplary packet filter format is depicted in FIG. 16. As shown inFIG. 16, the packet filter proposed in the present invention includesthe information such as application index or application ID.

The application analyzes the IP header of the data which is configuredin the UE to retrieve a matched filter and then extract the applicationindex or application ID configured in the filter when attempting datatransmission. Afterward, the UE checks the broadcast information todetermine whether the application is a baring target.

A description thereof is made with reference to FIG. 17.

FIG. 17 is a signal flow diagram illustrating the procedure of solution4 according to the second embodiment of the present invention.

-   -   S1705: The UE sends the MME an Attach Request message Including        PCO containing an application barring applicability indicator        and a packet filter analysis capability indicator indicating the        capability of analyzing a packet filter containing an        application ID or application index.    -   S1710, S1715: The MME sends the SGW/PGW the PCO information        received from the UE using a Create Session Request message.        Then the PGW saves the PCO information of the UE and performs        the attach procedure.    -   S1720: After the attach procedure, the PGW acquires the        information on the packet filter from the PCRF using the IP CAN        session modification/creation. At this time, the PGW request the        PCRF for the application list, and the PCRF sends the PGW a        response message including the application list. In the case of        using the application list stored in the PGW, step S1720 may be        omitted.    -   S1725: The PGW configures the packet filter including the        application index or application id in the field following the        packet filter content of the packet filter information formatted        as shown in FIG. 16. The PGW sends the MME the packet filter        through the Create Bearer Request message or the Update Bearer        Request message.    -   S1730: The MME sends the UE the information received from the        PGW through a Modify Bearer Request message or an Activate        Dedicated Bearer Request message.    -   S1735: The UE stores the packet filter including the application        index or application ID which is received from the MME.    -   S1740, S1745: The UE requests for opening the communication        service and then transmits the data.    -   S1750: The UE framework and modem (service framework/OS) checks        the matched packet filter based on the address and port        information of the IP packet transmitted by the application and        retrieves the application ID or application index included in        the corresponding packet filter. S1755: Meanwhile, the UE        acquires the application barring information from the SIB        broadcast by the eNB.    -   S1760: The UE determines whether the application index or        application ID corresponding to the transmitted data is barred        through the procedure of one of FIGS. 11 and 12. If the        application index or ID is barred, the UE notifies the        application that the communication is rejected through        process A. Otherwise if the application index or ID is not        barred, the UE sends the network the Attach Request message for        transitioning to the connected mode through process B.

THIRD EMBODIMENT

A description is made of the third embodiment of the procedure for theoperator to notify the UE of the application of the Operator DeterminedBarring.

Currently, a Call Barring service for the user to bar a certain call isdefined for use in IMS network. There are Barring of all incoming,Barring of all outgoing call, Barring of outgoing international call,and Barring of incoming call when roaming that are applied selectivelywhen requested by the user. However, there may be a case in that theoperators want to apply a certain barring service for a certain userarbitrarily to protect their profit. For example, it may be necessaryfor the operator to barring the outgoing or incoming call for a user whodoes not pay the communication fee.

In the conventional technology, however, any method for notifying theuser of the call barring applied according to the operator'sdetermination and clearing the session attempted by the UE is notspecified.

FIG. 18 is a schematic diagram illustrating EPS and IMS networks asbasis of an embodiment of the present invention. Descriptions are madebriefly of the entities related to the present invention among theentities depicted in FIG. 18 hereinafter.

Referring to FIG. 18, the User Equipment (UE) 1810 is a mobile terminal,and the eNB (E-UTRAN in the drawing) 1820 is an entity which controlsradio resource and is connected with the UE 1820 through a radiochannel.

The Mobility Management Entity (MME) 1830 is responsible for managingthe mobility of the UE 1810 in the idle mode and Roaming andAuthentication of the UE. The MME 1830 also processes the bearer signalgenerated by the UE 1810.

The Home Subscriber Server (HSS) 1840 stores the subscriber informationof each UE and provides the MME 1830 with the UE information, when theUE 1810 accesses the network, for use at the MME 1830 in controlling theUE 1810. The MME 1830 also stores the service profiles of the servicesprovided by the IMS network, which are to the UE 1810.

The Session Control Function (CSCF) of the IMS network includes a P-CSCF1850, an I-CSCF 1860, and an S-CSCF 1870. The P-CSCF 1850 denotes theProxy CSCF, and the S-CSCF 1870 denotes the Serving CSCF responsible forIMS session control and service control.

The TAS 1880 denotes the Telephony Application Server responsible forproviding supplementary service of the IMS call.

The barring of all outgoing call operation specified for the current IMSnetwork based on the above-described network structure can be depictedas shown in FIG. 19.

The user registers a supplementary service to bar placing an outgoingcall with the UE 1810 at step S1900. For the registration of thesupplementary service, the UE 1810 connects to a server of the operatoror a service provider to register the barring of all outgoing callservice. Then the supplementary service information registered by the UE1810 is shared with the TAS 1880, which identifies the outgoing call ofthe corresponding UE 1810 as a barred call.

Afterward, the UE 1810 sends the P-CSCF a REGISTER message forregistration with the IMS network at step S1905. Then the PCSCF forwardsthe REGISTER message to the SCSCF at step S1940.

The SCSCF 1870 downloads the service profile of the corresponding UE1801 from the HSS 1840 at step S1915. The service profile includes theinitial Filter Criteria (iFC). The SCSCF 1870 sends the PCSCF 1850 a200OK message at step S1920. Then the PCSCF 1850 forwards the 200OKmessage to the UE 1810 to reply in response to the REGISTER request.

In this way, the UE 1810 completes the procedure of registration withthe IMS network.

Afterward, the UE 1810 sends the PDSCF 1850 an INVITE message toinitiate the IMS session at step S1930. Then the PCSCF 1850 forwards theINVITE message to the SCSCF 1870 at step S1935.

The SCSCF 1870 checks the iFC of the UE 1810 at step S1940. According toiFC, the INVITE message transmitted by the UE 1810 is supposed to betransmitted to the TAS 1880. Accordingly, the SCSCF 1870 forwards theINVITE message to the TAS 1880 according to the iFC at step S1945.

The TAS 1880 checks that the outgoing call of the UE 1810 is barred andrejects the session request at step S1950. Then the TAS 1880 sends theUE a session reject message (603 Declined) at step S1955.

FIG. 20 is a signal flow diagram illustrating a procedure for the UE1810 to register with the IMS network and abiding by the ODB accordingto an embodiment of the present invention.

Summarizing the above embodiment of the present invention, the UE 1810to which ODB is applied receives a response message including anindicator indicating the session rejection from the TAS 1880. If theresponse message includes an action to be taken by the UE, the UE 1810takes the action as instructed. A description is made of the ODPapplication procedure in detail with reference to FIG. 20.

The operator or the service provider applies the Operator DeterminedBarring (ODB) to the UE 1810 and registers the UE-related context atstep S2005.

Afterward, the UE 1810 sends the PCSCF 1850 a REGISTER message forperforming registration procedure with the IMS network at step S2010.Then the PCSCF 1850 forwards the REGISTER message to the SCSCF 1870 atstep S2015.

Afterward, the SCSCF 1870 downloads the service profile of the UE 1810from the HSS 1840. The service profile includes the initial FilterCriteria (iFC). According to an embodiment of the present invention, theiFC includes the context for applying ODB.

The SCSCF 1870 sends the PCSCF 1850 a 200OK message at step S2025, andthe PCSCF 1850 forwards the 200OK message to the UE 1810.

The UE sends the PCSCF 1850 an INVITE message to initiate the IMSsession at step S2035. Then the PCSCF 1850 forwards the INVITE messageto the SCSCF 1870 at step S2040.

The SCSCF 1870 checks the iFC of the UE 1810 at step S2045. According toiFC, the INVITE message transmitted by the UE 1810 is supposed to betransmitted to the TAS 1880. Accordingly, the SCSCF 1870 forwards theINVITE message to the TAS 1880 according to the iFC at step S2050.

The TAS 1880 processes the corresponding session according to theinformation in the ODB context. The TAS 1880 may send the UE 1810 theresponse in the form of 3xx, 4xx, 5xx, and 6xx as shown in the stepssubsequent to S2060 and transfer the session to another recipient. Theembodiment of FIG. 20 is directed to the procedure of transmitting theresponse to the UE 1810.

The TAS 1880 sends the SCSCF 1870 the response message in reply to theINVITE message of the UE 1810. In this case, the response messageincludes the indicator informing that the session request is rejecteddue to the ODB.

An embodiment of the present invention proposes an ‘operator determinedbarring’ indicator as an example. This indicator may be included in theheader of the SIP message or in the form of a feature tag. Also, theindicator may be included in the SIP response message in a XML format.

Then the SCSCF 1870 sends the PCSCF 1850 the response message, and thePCSCF 1850 forwards the response message to the UE 1810.

The UE 1810 receives the response message and checks the ‘operatordetermined barring’ indicator included in the response message. The UE1810 may check that its session request is rejected by the ODB.

The UE 1810 also determines whether a Required_action is included in theresponse message. The information on the required action may be includedin the response message optionally. If the Required_action included inthe response message instruct to close the requested session, the UE1810 ends the session. If the required_action is not included, the UEmay take a default action. The default action may be preconfigured inthe UE or updated by the operator through the OMA-DM.

FIG. 21 is a diagram illustrating an exemplary response message proposedin an embodiment of the present invention.

As shown in FIG. 21, the response message may include the operatordetermined barring indicating that the session request is rejected andthe required_action information.

FIG. 22 is a diagram illustrating an exemplary UE context transmittedfrom the HSS to the TAS according to an embodiment of the presentinvention. The UE context is applied to step 2005 of FIG. 20.

The data reference is an arbitrary number.

The XML tag is the xml tag used in the data and, an embodiment of thepresent invention proposes IMS_ODB.

The Access key is a reference identity such as IMS public user identityor MSISDN for access to the data and applicable to Sh-Pull, Sh-Update,and Sh-Subs-Notif messages.

FIG. 23 is a diagram illustrating an exemplary XML schema used forimplementing ODB according to an embodiment of the present invention.

FIGS. 24 and 25 are signal flow diagrams illustrating a procedure forthe eNB to notify the MME of the occurrence or resolution of congestionon a specific channel according to an embodiment of the presentinvention.

Conceptually, the eNB may notify the MME of its congestion status usinga certain control message (e.g. S1-AP message) as shown at step S2410 orS2510. That is, the congestion information of the eNB may be piggybackedon a message transmitted to the MME for other purpose (e.g., InitialContext Setup Response). The congestion information piggybacked on acertain S1-AP message may include congestion presence/absence,congestion target (cell, PLMN, channel, etc.), congestion continuationtime, congestion level, and load level required to resolve thecongestion.

This embodiment is directed to an example of the congestion on thepaging channel. In FIG. 24, if the paging channel is congested, the eNBsends the MME an S1-AP message including the overload status information(e.g. Overload Start IE) at step S2410. The overload status informationmay include just a flag indicating that the overload situation has begunor the information on the congested object, i.e. PLMN ID of the cell,cell ID, congested channel (paging channel in this embodiment),congestion degree, load level required to resolve the congestion, andcongestion continuation time.

If the information on the start of the overload is received from theeNB, the MME regards that a specific PLMN, a specific cell, or aspecific channel is congested according to the information included inthe status information since then and, if the congestion continuationtime is included in the overload status information, starts a timer tocount the expiry of the timer as the end of the congestion. Although theS1-AP message received from the eNB is related to a specific UE, theoverload status information included in the corresponding S1-AP messagemay not be concerned with the specific UE.

As shown in FIG. 25, the MME may receive the overload status informationinforming that the target (specific PLMN, specific, cell, or specificchannel depending on the target information) is not congested any more(e.g. Overload Stop IE) from the eNB at step S2510. Then the MME regardsthis as the resolution of the congestion status to the target(corresponding cell or corresponding channel of PLMN). If the congestioncontinuation time is included in the overload status information, theMME regards the expiry of the congestion continuation timer as theresolution of the congestion.

Although the congestion continuation timer is not included in theoverload status information, the MME may starts a timer according to itsinternal time to count the running duration of the timer as thecontinuation of the congestion.

Although the eNB may use different IEs to notify of the start and end ofthe overload status as shown in FIGS. 24 and 25, it is also possible tonotify of those by inserting the Overload Status IE into a certaincontrol message (e.g. S1-AP message).

In this case, the eNB may notify of the overload status using theoverload flag of the overload status information or the congestion levelinformation or the overload level required to resolve the congestion. Inthis case, the congestion level required to resolve the congestion maybe set to 0. The eNB also may set the congestion continuation time ofthe overload status information to 0 to notify of the resolution of thecongestion status.

Each of the nodes of the wireless communication network presented in thedrawings and detail description may include a transceiver to transmitand receive signals to and from other nodes and a control unit forcontrolling the functions of the respective nodes. The detailedfunctions of the control unit of each node have been described in theabove embodiments, detailed descriptions thereof are omitted herein.

Although various embodiments of the present disclosure have beendescribed using specific terms, the specification and drawings are to beregarded in an illustrative rather than a restrictive sense in order tohelp understand the present invention. It is obvious to those skilled inthe art that various modifications and changes can be made theretowithout departing from the broader spirit and scope of the invention.

What is claimed is:
 1. A method performed by a gateway in a communication system, the method comprising: receiving, from a core network node, a downlink packet including header information, the header information including a value identifying an internet protocol (IP) multimedia subsystem (IMS) service; generating a downlink data notification message including paging policy information, the paging policy information including the value identifying the IMS service; and transmitting, to a mobility management entity, the downlink data notification message, wherein the paging policy information indicates that the mobility management entity identifies a paging strategy for the IMS service based on the paging policy information, and wherein the paging strategy includes information on a retransmission associated with a paging.
 2. The method of claim 1, wherein the paging strategy for the IMS service is used to perform a procedure associated with the paging by the mobility management entity.
 3. The method of claim 1, wherein the paging strategy for the IMS service is configured in the mobility management entity based on the paging policy information.
 4. The method of claim 1, wherein the paging policy information is associated with a quality of service class identifier (QCI)
 5. 5. A gateway in a communication system, the gateway comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from a core network node, a downlink packet including header information, the header information including a value identifying an internet protocol (IP) multimedia subsystem (IMS) service, generate a downlink data notification message including paging policy information, the paging policy information including the value identifying the IMS service, and transmit, to a mobility management entity, the downlink data notification message, wherein the paging policy information indicates that the mobility management entity identifies a paging strategy for the IMS service based on the paging policy information, and wherein the paging strategy includes information on a retransmission associated with a paging.
 6. The gateway of claim 5, wherein the paging strategy for the IMS service is used to perform a procedure associated with the paging by the mobility management entity.
 7. The gateway of claim 5, wherein the paging strategy for the IMS service is configured in the mobility management entity based on the paging policy information.
 8. The gateway of claim 5, wherein the paging policy information is associated with a quality of service class identifier (QCI)
 5. 9. A method performed by a mobility management entity in a communication system, the method comprising: receiving, from a gateway, a downlink data notification message for a downlink packet; identifying that the downlink data notification message includes paging policy information, the paging policy information including a value identifying an internet protocol (IP) multimedia subsystem (IMS) service; identifying a paging strategy for the IMS service based on the paging policy information, the paging strategy including information on a retransmission associated with a paging; and performing a procedure associated with the paging based on the paging strategy, wherein the value identifying the IMS service is included in header information of the downlink packet transmitted from a core network node to the gateway.
 10. The method of claim 9, wherein the paging policy information is associated with a quality of service class identifier (QCI)
 5. 11. The method of claim 9, wherein the downlink packet includes general packet radio service tunneling protocol user plane (GTP-U) packet.
 12. A mobility management entity in a communication system, the mobility management entity comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from a gateway, a downlink data notification message for a downlink packet, identify that the downlink data notification message includes paging policy information, the paging policy information including a value identifying an internet protocol (IP) multimedia subsystem (IMS) service, identify a paging strategy for the IMS service based on the paging policy information, the paging strategy including information on a retransmission associated with a paging, and perform a procedure associated with the paging based on the paging strategy, wherein the value identifying the IMS service is included in header information of the downlink packet transmitted from a core network node to the gateway.
 13. The mobility management entity of claim 12, wherein the paging policy information is associated with a quality of service class identifier (QCI)
 5. 14. The mobility management entity of claim 12, wherein the downlink packet includes general packet radio service tunneling protocol user plane (GTP-U) packet.
 15. The method of claim 1, wherein the paging strategy for the IMS service is different from a paging strategy for other service.
 16. The gateway of claim 5, wherein the paging strategy for the IMS service is different from a paging strategy for other service.
 17. The method of claim 9, wherein the paging strategy for the IMS service is different from a paging strategy for other service.
 18. The mobility management entity of claim 12, wherein the paging strategy for the IMS service is different from a paging strategy for other service. 